1. Field of the Invention
The present teachings relate to electrocatalyst compositions composed essentially of platinum, tungsten and a third metal, with platinum present in an atomic percentage ranging between about 20 percent and about 55 percent, tungsten present in an atomic percentage ranging between about 30 percent and about 75 percent, and the third metal present in an atomic percentage ranging between about 1 percent and about 40 percent. The third metal is at least one member selected from the group consisting of scandium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, yttrium, niobium, molybdenum, cadmium, tin, hafnium, tantalum and rhenium. The electrocatalyst compositions can also include a fourth metal and a fifth metal in atomic percentages ranging between about 1 percent and about 40 percent, wherein the fourth and fifth metals are, independently, at least one member selected from the group consisting of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, cadmium, tin, hafnium, tantalum and rhenium.
2. Discussion of the Related Art
The desire to reduce the amount of expensive platinum group metals needed to obtain a desired level of performance for an electrocatalyst is an ever present operational parameter for the design of many devices and procedures involving electrocatalysts.
Enhancement of catalytic performance by combining platinum with various less expensive metals is one of the possible avenues to either reduce the amount of platinum required, or perhaps increase the efficiency of the catalyzed reaction, or both. One application of interest for Pt-based electrocatalyst is, for instance, the cathode reaction of a typical proton exchange membrane fuel cell (“PEMFC”) which can utilize an electrode containing a Pt-based electrocatalyst to catalyze the oxygen reduction reaction.
A need exists for electrocatalyst compositions that reduce the amount of platinum needed to achieve a desired performance level.